How can you stop a pimple from growing?

SO RECENTLY, I HAD LIKE 3 pimples on one cheek. All at the same time and it sucks like... whatever. FOR GIRLS, everytime i%26#039;m about to have my period, it/they grow/s. :| LIKE, HOW CAN I STOP IT? BECAUSE THIS REALLY SUCKS LIKE HELL. Nobody likes zits. :| 8-| HELP ME? :||||toothpaste?